Apple's spectacularly responsive new MacBook Air is the best Air yet -- and might be the best MacBook, period

After all the hype about the new MacBook Air releases last week, all the oohing and aahing over the engineering that slipped a significant amount of power and capability into such a tiny package, I was ready to be somewhat disappointed by the new 13.3-inch MacBook Air that arrived on my doorstep earlier this week. I've used every MacBook Air since it was originally released, and I still use an 18-month-old Air for hours and hours every day. What could impress me about the new one? As it turns out, plenty.

My last Air was top-of-the-line, with a dual-core 2.13GHz CPU, 2GB of RAM, and the 128GB SSD, purchased in June 2009. I purchased a top-of-the-line model this time as well, bearing the same dual-core 2.13GHz CPU, but now with 4GB of RAM and 256GB of flash storage ($1,799 from the Apple Store). The difference in performance between the two is significant -- and that's saying something. The older model -- my daily workhorse -- is no slouch, at least until you run into heavy swap due to the 2GB of RAM. After all, the old model has the same CPU is the new one.

Still, applications like Mail, Safari, Microsoft Word, and others launch almost instantly on the new Air, and that's with Spotlight hammering the disk and CPU performing the indexing functions. The load average on the new Air is 1.85 with the Spotlight mds and mdworker processes claiming 150 percent of the CPU resources, and it's still easily beating the older Air in responsiveness. I should probably note here that I've had to disable the indexing services on many Windows 7 systems because indexing absolutely destroyed performance. I should also note that Spotlight was indexing around 100GB of data (transferred from my old machine) on the new Air (more on that transfer later).

New MacBook Air vs. old MacBook Air: Hardware improvementsA casual glance at the old and new Airs doesn't tell much of a tale. They closely resemble each other in size and shape, although the hinges on the new version appear to be much sturdier than those on the previous Air.

A closer look shows that much has changed. Gone are the underbelly curves in favor of the straight sides, and thankfully the new Air vents out the rear, not at a 45-degree angle toward the bottom.

There are now two USB 2.0 ports (one on either side), a SD card slot, a Mini DisplayPort, and a flat MagSafe power connector on the left-hand side. The additions of the second USB port and the SD card slot are certainly welcome, and the fact that you can finally use any Apple MagSafe power adapter with the Air laying flat on a table is long overdue. It was one of my biggest pet peeves of the older version.